More than 2 million Americans have such severe COPD (chronic obstructive pulmonary disease) that they cannot even climb a single flight of stairs, due to the feeling of suffocation with even minimal movement. These patients suffer like this for years, first becoming essentially home-bound, then chair-bound, and eventually bed-bound. This lack of physical activity has been repeatedly shown to increase the frequency of hospitalization, the major driver of cost in COPD. The standard of COPD care is grossly inadequate and is composed of two main therapies. First are inhalers (bronchodilators and corticosteroids), which only marginally improve shortness of breath. Second is supplemental oxygen, which increases lifespan but does very little for shortness of breath. Our patient population is defined as the 2 million COPD patients who are on maximal medical therapy (inhalers + oxygen) but still cannot climb a single flight of stairs due to terrible shortness of breath. Activities proposed in the project will contribute to human health by providing the first wearable negative pressure ventilator for COPD patients, relieving them of exertional dyspnea, allowing them to reengage in normal exercise and daily activities, and keeping them out of the hospital. To solve this enormous need in COPD, we invented the AIR-AD. The AIR-AD looks like a regular clothing vest, but it dramatically offloads work of breathing and reduces dynamic hyperinflation, thereby markedly ameliorating dyspnea on exertion, allowing patients to increase their physical activity and stay out of the hospital. With each breath in, the AIR-AD generates a vacuum within the shell that helps lift the chest and abdomen, helping the patient inspire. With each breath out, the AIR-AD increases pressure over the chest and helps the patient breath out faster. We have researched the viability of this idea through the NSF I- Corps project. The responses of the interviewed patients, healthcare providers, and hospital administrators were overwhelmingly positive. During the proposed project, we will perform human factors analysis by interviewing patients to establish key design features and user needs (Aim 1a). We will develop a novel respiratory pattern sensor for accurate breathing detection during ambulation and talking (Aim 2). Finally, we will perform a pilot testing of the patient-preference-designed AIR-A (Aim 3). At the end of research and development in Phase 1, we will have developed and verified a prototype AIR-AD device, proving that a wearable device can perform as well as stationary CVs in terms of pressure ranges, breathing frequency, and breathing synchrony, but have good mobility, patient comfort, and patient acceptance while walking. At that point, we will have sufficient evidence to support the development and clinical testing of the final AIR-AD device in a Phase 2 SBIR.